Using multiple versions of Rails without gemsets

gistfile1.txt

# RubyGems has this functionality built-in. Just specify
# the particular version you want to use as the first argument
# of the command, surrounded by underscores.

$ gem install rails --version 3.0.9
...
$ gem install rails --pre
...
$ rbenv rehash
$ rails --version
Rails 3.1.0.rc5
$ rails _3.0.9_ --version
Rails 3.0.9

You know, I have always seen this in the bin stubs installed by RubyGems, but never thought of using it, nor remember it when needed. Thanks for the reminder!